The use of automatic controlled equipment for cutting large quantities of pattern pieces from sheet material, such as fabrics from which wearing apparel, upholstery, structural material and other articles are made has necessitated the need for a cutting tool whose operation does not damage the cut material nor decrease the throughput of the automatic controlled equipment. Such cutting systems have employed mechanical cutters including knife and chisel type cutters operating in a reciprocating fashion. In cutting mechanisms using a knife type cutter, a reciprocating cutting blade is generally stroked in a direction normal to the sheet material to penetrate the material as the cutting edge or blade is advanced or guided along a predetermined cutting path by automatic controls. In such reciprocating cutters, during any cut cycle, the velocity vector of the cutting blade follows a sinusoidal path having two zero velocity points during the cycle. The cutter reaches zero velocity when it has been completely withdrawn from the sheet material and zero velocity when it impacts the sheet material supporting surface.
The occurrence of these two zero velocity points during any cycle typically causes excess material movement in the zero velocity region because of low cutting blade velocity and movement of the cutting machine support system. In cutting plastic materials and composite materials such as, for example, shoe material and fiberglass layered materials, the reciprocation rates of cutting tools produce sufficient heat in the material to cause localized heating, thereby causing fusion of adjacent plies of the layup of material being cut. As the cutting blade is drawn in and out of the sheet material, a drag force is created on the cutting blade producing an additional source of heat. Further, the reciprocating motion of the cutting blade causes displacement of the cut sheet material. Additionally, localized heating creates problems such as heat distortion and premature epoxy cure in fiberglass layered material being cut. The fusing of adjacent plies of the material, in addition to damaging the material, causes difficulty in separation of pattern pieces during later stages of the manufacturing process where the pieces are, for example, sewn or otherwise assembled with other pattern pieces.
A need has thus arisen for a cutting tool for use in a system for cutting plies of material, such as composite material, that prevents or substantially minimizes localized heating with no resulting part contamination. Furthermore, a need has arisen for a cutting tool that does not create fiber fringing, fiber separation and material displacement during the cutting operation. A need has further arisen for a cutting tool in which heat generation, during a cutting cycle, is minimized to thereby prevent premature epoxy cure and eliminate adhesion to the cutting tool due to epoxy tack.